Glossary
SKU (Stock Keeping Unit)
SKU (Stock Keeping Unit) is a unique alphanumeric identifier assigned to each distinct product and its variants — size, color, configuration — within an inventory management system. In paid media and ecommerce advertising, SKUs are the atomic unit of Shopping Ads and Performance Max campaigns: each SKU uploaded to Google Merchant Center generates its own product listing with unique attributes including title, description, image, price, and availability status. SKU-level data enables granular performance analysis that aggregate campaign metrics obscure — advertisers can identify which specific products drive the highest ROAS, which suffer from low conversion rates despite strong impressions, and which should be excluded from campaigns entirely. Feed optimization at the SKU level — improving product titles for search relevance, using high-quality images, and maintaining accurate price and availability data — directly impacts impression share, click-through rate, and cost-per-click in Shopping campaigns. A well-structured SKU taxonomy that separates products by margin, category, and seasonality is the foundation of profitable ecommerce PPC management.